Like the kellener sport module, the tuning box uses piggybacking. This chip/cartridge is connect to the obd2 diagnostics port in the cars cabin. What controls the engines performance is the ECU(engine control unit),BMW driver experience switch changes numbers on the ECU(ECO pro,comfort and sport). But the tuning box also has a separate ECU preprogrammed for the N20 and other engines. When you plug it in the BMW ECU is untouched/skipped and the tuning box is now the primary ECU. When removed the original BMW ECU is now primary again.

Now I know Dinan offers there own warranty because they reprogram the original BMW ECU hence BMW warranty is voided.

Problem here is I don't think TMC fully tests there performance upgrade on the car aka wear and tear on the transmission. Dinan is a better tuner but reprogramming the ECU is a no no for BMW warranty. Kellener Sport seems the best since its also a piggybacking chip and they are a renowned German performance tuner for BMW but it costs $2000.

My suggestion is if you will take your car to the track then get the Dinan or Kellener Sport module since they test under track conditions.

If you are like me and just want a performance boost for a everyday driving pleasure get the TMC.

Installation of the TMC tuning box and the Kellener Sport Module is as simple as plugging in a super mario cartridge in to a nintendo. Just make sure the car is off when you do.

TMC Motorsport and Kellener Sport has a box for the 320i, 328i, 335i and many other engines. Just waiting on Dinan to release something but they are probably heavily testing as we speak.

That is the catch. If TMC were to provide long term evidence of the mod not impacting the durability or taking the car outside of specs, then it would provide a solid argument for coverage under the MM. By the way, most people still are not clear on what the MM provides. It simple states that by adding an aftermarket modification to a car, does not explicitly void a warranty. In fact the FTC just recently reiterated that its the manufacturers job to prove that the mod cause the issue. Perfect example was aftermarket exhaust system, and the dealer refusing to fix a radio or power seat. Clearly the mod did not cause it.